Method for mounting parts on circuit boards

Abstract

One or more parts having terminals can be mounted on a circuit board by coating an ultraviolet-curing and thermosetting resin composition comprising an ultraviolet-curing resin, an addition polymerizable monomer, a photosensitizer and a heat polymerization initiator, on the circuit board by screen printing with a prescribed pattern, mounting the parts on the printed resin composition, curing the resin composition by simultaneous irradiation of ultraviolet light and heat rays so as to bond the parts to the circuit board, and soldering the parts onto the circuit board.

What is claimed is: 
     
       1. A method for mounting one or more parts having terminals on a circuit board which comprises coating an ultraviolet-curing and thermosetting resin composition on the circuit board by screen printing with a prescribed pattern except for wiring portions of the circuit board, mounting the parts on the printed resin composition, curing the resin composition by simultaneous irradiation of ultraviolet light and heat rays so as to bond the parts to the circuit board, and soldering the terminals of the parts onto the wiring of the circuit board. 
     
     
       2. A method according to claim 1, wherein the ultraviolet-curing and thermosetting resin composition comprises (a) 100 parts by weight of at least one ultraviolet-curing resin,   (b) 5 to 70 parts by weight of at least one addition polymerizable monomer having at least one ethylenically unsaturated group (CH 2  ═C<) and a boiling point of 100° C. or more at atmospheric pressure,   (c) 0.05 to 5 parts by weight of at least one photosensitizer, and   (d) 0.05 to 5 parts by weight of a heat polymerization initiator.   
     
     
       3. A method according to claim 2, wherein the ultraviolet-curing resin is an unsaturated polyester, an unsaturated polyurethane, an epoxy acrylate resin, a 1,2-polybutadiene having terminal acryloyl, acryloyloxy, methacryloyl or methacryloyloxy groups and a molecular weight of 500 to 10,000, or a polyorganosiloxane having terminal acryloyl, acryloyloxy, methacryloyl or methacryloyloxy groups and a molecular weight of 500 to 10,000. 
     
     
       4. A method according to claim 2, wherein the addition polymerizable monomer is styrene, a styrene derivative, acrylic acid, a derivative of acrylic acid, methacrylic acid, a derivative of methacrylic acid, a polyfunctional acrylic or methacrylic ester having two or more unsaturated groups, or a polyfunctional vinyl monomer. 
     
     
       5. A method according to claim 2, wherein the photosensitizer is benzoin, a derivative of benzoin, a benzoin ether, benzil, a derivative of benzil, an aryl diazonium salt, anthraquinone, a derivative of anthraquinone, acetophenone, a derivative of acetophenone, diphenyl disulfide, benzophenone or a derivative of benzophenone. 
     
     
       6. A method according to claim 2, wherein the heat polymerization initiator is an organic perioxide or an azo compound. 
     
     
       7. A method according to claim 2, wherein the heat polymerization initiator is benzoyl peroxide, acetyl peroxide, lauroyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, or 2,2'-azobis(methyl isobutyrate). 
     
     
       8. A method for mounting one or more parts having terminals on a circuit board which comprises coating an ultraviolet-curing and thermosetting resin composition comprising (a) 100 parts by weight of at least one ultraviolet-curing resin selected from the group consisting of an unsaturated polyester, an unsaturated polyurethane, an epoxy acrylate resin, a 1,2-polybutadiene having terminal acryloyl, acryloyloxy, methacryloyl or methacryloyloxy groups and a molecular weight of 500 to 10,000, and a polyorganosiloxane having terminal acryloyl, acryloyloxy, methacryloyl or methacryloyloxy groups and a molecular weight of 500 to 10,000,   (b) 5 to 70 parts by weight of at least one addition polymerizable monomer having at least one ethylenically unsaturated group and a boiling point of 100° C. or more at atmospheric pressure selected from the group consisting of styrene, vinyltoluene, acrylic acid, butyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methacrylic acid, ethyl methacrylate, lauryl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, polyethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, diallyl phthalate and divinyl benzene,   (c) 0.05 to 5 parts by weight of a photosensitizer selected from the group consisting of benzoin, 4,4'-dimethyl benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzil, 4,4'-dimethyl benzil, benzene diazonium chloride, anthraquinone, 2-methylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, acetophenone, 4-methoxyacetophenone, diphenyl disulfide, diethyl disulfide, benzophenone and 4-methoxybenzophenone,   (d) 0.05 to 5 parts by weight of a heat polymerization initiator selected from the group consisting of benzoyl peroxide, acetyl peroxide, lauroyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile and 2,2'-azobis(methyl isobutyrate), on the circuit board by screen printing with a prescribed pattern except for wiring portions of the circuit board,   mounting the parts on the printed resin composition,   curing the resin composition by simultaneous irradiation of ultraviolet light and heat rays so as to bond the parts to the circuit board, and   soldering the terminals of the parts onto the wiring of the circuit board.   
     
     
       9. A method according to claim 8, wherein the ultraviolet-curing and thermosetting resin composition further comprises 300 parts by weight or less of one or more fillers, 10 parts by weight or less of one or more thixotropic agents and 0.1 to 10 parts by weight of one or more adhesion imparting agents. 
     
     
       10. A method according to claim 1, 8 or 9, wherein ultraviolet light and heat rays are produced by a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a carbon arc lamp or a xenon lamp. 
     
     
       11. A method according to claim 9, wherein the filler is a powder of aluminum oxide, silicon dioxide, calcium carbonate, titanium dioxide, barium sulfate or mica, the thixotropic agent is pulverized silicon dioxide having a specific surface area of 100 to 450 m 2  /g, and the adhesion imparting agent is γ-methacryloyloxypropyltrimethoxysilane or vinyltris(β-methoxyethoxy)silane.